US7307535B2 - Air coil RF transponder and method of making same - Google Patents

Air coil RF transponder and method of making same Download PDF

Info

Publication number
US7307535B2
US7307535B2 US10899869 US89986904A US7307535B2 US 7307535 B2 US7307535 B2 US 7307535B2 US 10899869 US10899869 US 10899869 US 89986904 A US89986904 A US 89986904A US 7307535 B2 US7307535 B2 US 7307535B2
Authority
US
Grant status
Grant
Patent type
Prior art keywords
transponder
resonant
coil
body
frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US10899869
Other versions
US20060022830A1 (en )
Inventor
Sileno Oggian
Roberto Malfanti
Takamasa Ishii
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Datamars SA
Original Assignee
Datamars SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/04Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the shape
    • G06K19/041Constructional details
    • G06K19/047Constructional details the record carrier being shaped as a coin or a gambling token
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/0723Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
    • G06K19/0726Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G06K19/07773Antenna details
    • G06K19/07777Antenna details the antenna being of the inductive type
    • G06K19/07779Antenna details the antenna being of the inductive type the inductive antenna being a coil
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G06K19/07773Antenna details
    • G06K19/07777Antenna details the antenna being of the inductive type
    • G06K19/07779Antenna details the antenna being of the inductive type the inductive antenna being a coil
    • G06K19/07781Antenna details the antenna being of the inductive type the inductive antenna being a coil the coil being fabricated in a winding process

Abstract

An RF air coil transponder includes a rotatable carrier, such as a rigid reel. A coil is wound about the reel and at least one field influencing body for influencing the electric and/or the magnetic field within the coil is supported by the reel. The rigidity of the reel enables the coil to keep its form and guarantees precise distances between windings, especially when a winding machine forms the coil. Adjusting the angular position, shape, composition, size, and/or surface are of the body effects adjustment of the resonant frequency.

Description

BACKGROUND OF THE INVENTION

This invention is related to RF transponders and, in particular, to RF air coil transponders and to methods of making the same.

In radio frequency identification systems, the resonant frequency of the transponders is one of the most important factors in the reading performance of the transponders. Precise resonant frequency of the transponders helps to guarantee the electrical functionality quality of the product.

Often, some transponders demonstrate different reading performance and this difference often comes from differences of the resonant frequencies. This, in turn, is often caused by the technology used. For example, for low frequency transponders, such as 125 kHz transponders, and middle frequency transponders, such as 13.56 MHz transponders, usually air coil technology is used.

Generally, in the manufacture of air coil transponders, the air coils are made from conventional single insulated wires, which typically are self-adhering. If self-adhesive wires are used, this could result in the coils being solid and difficult to be deformed if the number of windings is high. On the other hand, if the number of windings is low, such as 1 to 50 turns, the coil could be fragile and easily deformable. If the coil is deformed, impedance of the coil is also changed.

Further, every coil comprises inductance, resistance and parasitic capacitance. If the distance between wire turns and the wiring process differs from one transponder to another, the internal parasitic capacitance will also be different, resulting in differences between the impedances of the coils. This, in turn, results in a difference in resonant frequencies.

It is known to adjust the resonant frequency of transponders by changing the capacitance and/or changing the inductance of the resonant circuit of the transponders.

A very high Q (quality factor) resonant circuit is particularly effective in capturing high energy from the reading device and re-transmitting energy to the reading device, particularly at longer reading ranges. On the other hand, a high Q circuit does not allow for wide tolerances of resonant frequency because frequency differences create high differences on the coupling of energy from the reader to the transponder and transmit less energy from the transponder to the reader. This not only reduces the maximum reading distance but also results in variations of maximum reading distance between transponders.

For this reason, more precise resonant frequency is necessary for a high Q resonant circuit maximize the reading distance and to minimize the differences between transponders.

In addition to problems of controlling resonant frequency due to variations caused by differences between transponder coils, problems can also result from variations in the associated electronic components. Thus, for example, the ICs (integrated Circuits) employed, have capacitors that affect the resonant frequencies and tolerance variations between the capacitor ICs, therefore, will cause variations in resonant frequency of the transponders.

The variations in coil electrical parameters and/or variations caused by electrical component tolerances necessitate an effective technique for adjusting resonant frequencies before during or after manufacturing.

SUMMARY OF THE INVENTION

It is an object of the invention to provide RF air coils with precise impedance and to methods of making the same.

It is also an object of the invention to provide a method for adjusting resonant frequency of RF air coil transponders during and/or after production of the transponders.

In accordance with an aspect of the invention, using rigid carriers, such as rigid reels, reduces the impedance tolerances of air coils. The rigid carriers enable uniform winding of the coil.

In accordance with another aspect of the invention, a body made of a material, which influences the magnetic field, and/or electric field is provided. The shape, size, composition and/or position of the body are adjusted to change inductance and internal parasitic capacitance of the coil, thereby adjusting the resonant frequency of the transponder resonant circuit.

Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is an exploded, perspective view, with parts removed for the sake of clarity of a transponder illustrating certain features of the present invention.

FIG. 2 is a cross-sectional plan view of a carrier forming part of the transponder of FIG. 1,

FIG. 3 is an equivalent circuit of a coil forming part of the transponder of FIG. 1.

FIG. 4 is a block diagram showing a transponder being tested to determine its resonant frequency.

FIGS. 5 a-5 d are cross-sectional views showing the different orientation of the transponder carrier corresponding to different resonant frequencies.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and, in particular, to FIGS. 1 and 2, there is shown an RF air coil transponder 10 having a casing 11 (only the lower half of which is shown) and a rotatable carrier in the form of a rigid reel 12 made of a suitable electrically insulating material, such as plastic, e.g., PPS, mounted within the casing 11. Like the reel 12, the casing 11 may also be made of plastic, such as PPS. Advantageously, the requisite rigidity of the reel 14 is achieved by making the reel 12 solid. A coil 14 is wound about the reel 12. At least one body 16 for influencing the field, either electrical or magnetic, within the coil 14 is mounted on the reel 12. Although in this embodiment, the body 16 has a cylindrical shape, the body 16 may have any shape and may be composed of any suitable field influencing material, such as magnetic metals or ferrites. Aluminum has proven to be an effective material. Additionally, although only one body 16 is shown, in the practice of the invention one or more field influencing bodies 16 may be mounted on the reel 12. Another field influencing body 17 is affixed to the lower half 11 a of the casing 11. Like the body 16, the body 17 may have any shape and may be composed of any suitable material, such as aluminum. An IC (Integrated Circuit) 18 containing electrical components of transponder 10 is attached to the reel 12.

Referring to FIG. 3, there is shown an equivalent circuit 20 of the coil 14. The equivalent circuit 20 includes an inductor 22 representing the inductance of the coil 14, a resistor 24 representing the internal resistance of the coil 14, and capacitors 26 and 28 representing the internal parasitic capacitances of the coil 14. The inductor 22, the resistor 24 and the capacitors 26 and 28 constitute the impedance of the coil 14.

The resonant frequency of the coil 14 is a function of, among other things, the respective values of the inductor 22 and capacitors 26 and 28. In turn, these values, as is well known, are functions of, among other things, the distances between windings of the coil 14 and the form of the coil 14. Thus, if each transponder 10 had the same distance between the windings of the coil 14 and the same coil form, the values of the inductor 22 and capacitors 26 and 28 of the coil 14 of each transponder would be essentially the same, as would the resonant frequency. Unfortunately, the design of prior art transponders and their manufacture has not been such as to provide to uniform values. The present invention, however, enables such uniform values to be achieved.

Thus, the rigidity of the reel 12 enables the coil 14 to keep its form and guarantees precise distances between windings, especially when a winding machine forms the coil. This, in turn, enables constant values of inductance and parasitic capacitance, which, in turn, results in a constant resonant frequency.

As noted above, the bodies 16 and 17 influences the magnetic and/or electric field and, consequently, the total impedance of the coil 14 and the resonant frequency.

The ability of the bodies 16 and 17 to influence the magnetic field and/or electric field not only depends, as noted above, on the type of material from which the bodies 16 and 17 are made and their shape, particularly their surface areas, but also the angular position of the body 16.

In accordance with the present invention, the shape and composition of the bodies 16 and 17 are selected to achieve a desired resonant frequency. The resonant frequency of the transponder 10 is then tested, as seen in FIG. 4, with suitable test equipment 30. If the results of the testing indicate that the transponder 10 under test does not have the desired resonant frequency, the angular position of the body 16 is changed by rotating the carrier.

Referring to FIGS. 5 a-5 d, there are shown different angular positions of the body 16. Changing the position of the body 16, changes the impedance of the resonant circuit 20 and, hence, changes the resonant frequency of the transponder 10. More specifically, changing the position of the body 16 with respect to the body 17 changes the combined surface areas of the bodies 16 and 17. Changing the combined surface areas, in turn, changes the impedance of the coil 14. More specifically, the greater the combined surface areas, the higher the impedance. Thus, the combined surface areas of the bodies 16 and 17 in FIG. 5 b have more surface area than in FIG. 5 a. As a result, the resonant circuit 20 of transponder 10 of FIG. 5 b has more impedance than the resonant circuit 20 of the transponder 10 of FIG. 5 a and consequently a lower resonant frequency. Similarly, the resonant circuit 20 of the transponder 10 of FIG. 5 c has more impedance than the transponder 10 of FIG. 5 b and consequently a lower resonant frequency. The position of the body 16 shown in FIG. 5 d results in the greatest combined surface areas and thus the resonant circuit 20 of FIG. 5 d has higher impedance than the resonant circuits of FIGS. 5 a-5 c, resulting in the lowest resonant frequency. Thus, adjusting the position of the body 16 in a clockwise direction decreases the resonant frequency of the transponder 10 relative to the position before.

Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.

Claims (32)

1. An RF transponder comprising:
a rotatable carrier;
a coil wound about the carrier; and
at least one field influencing body supported by the carrier within the coil, wherein an angular position, a shape, a composition, a size, and/or a surface area of the body influences the resonant frequency of the transponder.
2. An RF transponder according to claim 1, wherein the angular position of the body influences the resonant frequency of the transponder.
3. An RF transponder according to claim 1, wherein the shape of the body influences the resonant frequency of the transponder.
4. An RF transponder according to claim 1, wherein the composition of the body influences the resonant frequency of the transponder.
5. An RF transponder according to claim 1, wherein the size of the body influences the resonant frequency of the transponder.
6. An RF transponder according to claim 1, wherein the surface area of the body influences the resonant frequency of the transponder.
7. An RF transponder according to claim 1, including electrical components supported by the carrier.
8. An RF transponder according to claim 7, wherein the electrical components are embodied in an integrated circuit.
9. An RF transponder according to claim 4, wherein the body is composed of a magnetic material.
10. An RF transponder according to claim 9, wherein the magnetic material is aluminum.
11. An RF transponder comprising:
a casing;
a rotatable carrier disposed within the casing and rotatable with respect thereto;
a coil wound about the carrier;
at least one first field influencing body supported by the carrier within the coil; and
at least one second field influencing body affixed to the casing.
12. An RF transponder according to claim 11, including electrical components supported by the carrier.
13. An RF transponder according to claim 12, wherein the electrical components are embodied in an integrated circuit.
14. An RF transponder according to claim 11, wherein the first and second bodies are composed of a magnetic material.
15. An RF transponder according to claim 11, wherein each of the first and second bodies is composed of aluminum.
16. An RF transponder comprising:
a casing;
a coil disposed within the casing;
at least one moveable field influencing body within the coil; and
at least one fixed field influencing body with the coil.
17. A method of manufacturing an RF transponder comprising:
providing a rotatable carrier;
winding a coil about the carrier;
providing a casing:
disposing the rotatable carrier rotatably within the casing;
providing at least one first field inducing body supported by the carrier within the coil; and
providing at least one second field influencing body affixed to the casing.
18. A method of manufacturing an RF transponder comprising:
providing a casing;
providing a coil disposed within the casing;
providing at least one moveable field influencing body within the coil; and
providing at least one fixed field influencing body with the coil.
19. A method of manufacturing an RF transponder comprising:
providing a rotatable carrier;
winding a coil about the carrier; and
providing at least one field influencing body supported by the carrier within the coil, wherein an angular position, a shape, a composition, a size, and/or a surface area of the body influences the resonant frequency of the transponder.
20. The method of claim 19, wherein the angular position of the body influences the resonant frequency of the transponder.
21. The method of claim 19, wherein the shape of the body influences the resonant frequency of the transponder.
22. The method of claim 19, wherein the composition of the body influences the resonant frequency of the transponder.
23. The method of claim 19, wherein the size of the body influences the resonant frequency of the transponder.
24. The method of claim 19, wherein the surface area of the body influences the resonant frequency of the transponder.
25. The method of claim 19, including attaching electrical components to the carrier.
26. The method of claim 25, wherein the electrical components are embodied in an integrated circuit.
27. The method of claim 19, wherein the body is composed of a magnetic material.
28. The method of claim 27, wherein the magnetic material is aluminum.
29. A method of adjusting the resonant frequency of an RF transponder to a desired value, the RF transponder having a rotatable carrier, a coil wound about the carrier and at least one field influencing body supported by the carrier, which method comprises:
measuring a resonant frequency of the transponder; and
if the resonant frequency is not at the desired value, changing the angular position of the body such that the transponder has the desired resonant frequency.
30. The method of claim 29, wherein the carrier is rotatable and the angular position of the body is changed by rotating the carrier.
31. A method of adjusting the resonant frequency of an RF transponder to a desired value, the RF transponder having a casing, a coil disposed within the casing, at least one movable field influencing body within the coil, and at least one fixed field influencing body disposed with one coil, which method comprises:
measuring a resonant frequency of the transponder; and
if the resonant frequency is not at the desired value, changing the position of the at least one movable field influencing body such that the transponder has the desired resonant frequency.
32. The method of claim 31, wherein the at least one movable body is mounted on a rotatable carrier and the position of the at least one movable body is changed by rotating the carrier.
US10899869 2004-07-27 2004-07-27 Air coil RF transponder and method of making same Expired - Fee Related US7307535B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10899869 US7307535B2 (en) 2004-07-27 2004-07-27 Air coil RF transponder and method of making same

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US10899869 US7307535B2 (en) 2004-07-27 2004-07-27 Air coil RF transponder and method of making same
ES05405448T ES2297656T3 (en) 2004-07-27 2005-07-20 Transponder rf coil air core and manufacturing method thereof.
EP20050405448 EP1622070B1 (en) 2004-07-27 2005-07-20 RF Transponder and method of tuning its frequency
DE200560003990 DE602005003990T2 (en) 2004-07-27 2005-07-20 RF transponder and method for frequency tuning
US12001787 US20080311868A1 (en) 2004-07-27 2007-12-11 Air coil RF transponder and method of making same

Publications (2)

Publication Number Publication Date
US20060022830A1 true US20060022830A1 (en) 2006-02-02
US7307535B2 true US7307535B2 (en) 2007-12-11

Family

ID=35149542

Family Applications (2)

Application Number Title Priority Date Filing Date
US10899869 Expired - Fee Related US7307535B2 (en) 2004-07-27 2004-07-27 Air coil RF transponder and method of making same
US12001787 Abandoned US20080311868A1 (en) 2004-07-27 2007-12-11 Air coil RF transponder and method of making same

Family Applications After (1)

Application Number Title Priority Date Filing Date
US12001787 Abandoned US20080311868A1 (en) 2004-07-27 2007-12-11 Air coil RF transponder and method of making same

Country Status (4)

Country Link
US (2) US7307535B2 (en)
EP (1) EP1622070B1 (en)
DE (1) DE602005003990T2 (en)
ES (1) ES2297656T3 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7432808B2 (en) * 2004-12-15 2008-10-07 Intel Corporation Wireless module enabled component carrier for parts inventory and tracking
WO2010005576A3 (en) * 2008-07-10 2010-03-04 Radarfind Corporation Rotatable tags for automated location and monitoring of moveable objects and related systems

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5025550A (en) * 1990-05-25 1991-06-25 Trovan Limited Automated method for the manufacture of small implantable transponder devices
US5814986A (en) * 1997-03-18 1998-09-29 Eaton Corporation Coil retainer/positioner for inductive proximity sensor
US6067235A (en) * 1995-03-22 2000-05-23 Finn; David Process and a device for the production of a transponder unit and a transponder unit
US6246328B1 (en) * 2000-05-16 2001-06-12 Timothy A. Parkinson Extended range passive marker
US6380857B1 (en) * 2000-10-16 2002-04-30 Industrial Technology, Inc. Self leveling underground marker
US6412722B1 (en) * 1998-05-13 2002-07-02 Pure Fishing, Inc. Bait cast control fishing reel
US6496154B2 (en) * 2000-01-10 2002-12-17 Charles M. Gyenes Frequency adjustable mobile antenna and method of making
US6778089B2 (en) * 1999-05-17 2004-08-17 Avid Identification Systems, Inc. Overmolded transponder
US20050172150A1 (en) * 2004-02-04 2005-08-04 Peter Schmitt Security device for data carriers
US7019711B2 (en) * 2002-12-16 2006-03-28 The Goodyear Tire & Rubber Company Coupled transponder and antenna system and method
US7135978B2 (en) * 2001-09-14 2006-11-14 Calypso Medical Technologies, Inc. Miniature resonating marker assembly

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4712094A (en) * 1986-05-29 1987-12-08 Minnesota Mining And Manufacturing Company Self-orienting passive marker structure
NL9200835A (en) * 1992-05-11 1993-12-01 Nedap Nv Flexible coil construction identification card.
EP0782214B1 (en) * 1995-12-22 2004-10-06 Texas Instruments France Ring antennas for resonant cicuits
FR2744863B1 (en) * 1996-02-13 1998-03-06 Schlumberger Ind Sa A method of making a portable object has coil antenna
US6097293A (en) * 1999-04-15 2000-08-01 Industrial Technology, Inc. Passive electrical marker for underground use and method of making thereof

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5025550A (en) * 1990-05-25 1991-06-25 Trovan Limited Automated method for the manufacture of small implantable transponder devices
US6067235A (en) * 1995-03-22 2000-05-23 Finn; David Process and a device for the production of a transponder unit and a transponder unit
US5814986A (en) * 1997-03-18 1998-09-29 Eaton Corporation Coil retainer/positioner for inductive proximity sensor
US6412722B1 (en) * 1998-05-13 2002-07-02 Pure Fishing, Inc. Bait cast control fishing reel
US6778089B2 (en) * 1999-05-17 2004-08-17 Avid Identification Systems, Inc. Overmolded transponder
US6496154B2 (en) * 2000-01-10 2002-12-17 Charles M. Gyenes Frequency adjustable mobile antenna and method of making
US6246328B1 (en) * 2000-05-16 2001-06-12 Timothy A. Parkinson Extended range passive marker
US6380857B1 (en) * 2000-10-16 2002-04-30 Industrial Technology, Inc. Self leveling underground marker
US7135978B2 (en) * 2001-09-14 2006-11-14 Calypso Medical Technologies, Inc. Miniature resonating marker assembly
US7019711B2 (en) * 2002-12-16 2006-03-28 The Goodyear Tire & Rubber Company Coupled transponder and antenna system and method
US20050172150A1 (en) * 2004-02-04 2005-08-04 Peter Schmitt Security device for data carriers

Also Published As

Publication number Publication date Type
US20060022830A1 (en) 2006-02-02 application
DE602005003990D1 (en) 2008-02-07 grant
EP1622070B1 (en) 2007-12-26 grant
EP1622070A1 (en) 2006-02-01 application
US20080311868A1 (en) 2008-12-18 application
ES2297656T3 (en) 2008-05-01 grant
DE602005003990T2 (en) 2008-08-07 grant

Similar Documents

Publication Publication Date Title
US6028561A (en) Tunable slot antenna
US6496382B1 (en) Radio frequency identification tag
US4101899A (en) Compact low-profile electrically small vhf antenna
US5563582A (en) Integrated air coil and capacitor and method of making the same
US6005467A (en) Trimmable inductor
EP1439487A2 (en) Portable information device
US5955723A (en) Contactless chip card
US6690257B2 (en) Common mode choke coil
US5258765A (en) Rod-shaped multi-band antenna
US20070126544A1 (en) Inductive component
US6163300A (en) Multi-band antenna suitable for use in a mobile radio device
US6147655A (en) Flat loop antenna in a single plane for use in radio frequency identification tags
US20090262041A1 (en) Wireless ic device
US20120223149A1 (en) Antenna and rfid device
US3992691A (en) Electronic circuit board flat coil inductor
US6452473B1 (en) Multilayer inductor and method of manufacturing the same
EP0909024A2 (en) Impedance matching device
US20080186245A1 (en) Rfid Tag Having a Folded Dipole
US20070095926A1 (en) RFID tag with improved range
US8339233B2 (en) Three dimensional inductor
JP2004343410A (en) Non-contact communication type information carrier
EP0706231A1 (en) Antenna equipment
EP0863571A2 (en) A mobile image apparatus and an antenna apparatus used for the mobile image apparatus
US5874926A (en) Matching circuit and antenna apparatus
US20080129629A1 (en) Magnetic antenna and board mounted with the same

Legal Events

Date Code Title Description
AS Assignment

Owner name: DATAMARS S.A., SWITZERLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:OGGIAN, SILENO;MALFANTI, ROBERTO;ISHII, TAKAMASA;REEL/FRAME:015978/0313

Effective date: 20041104

FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Expired due to failure to pay maintenance fee

Effective date: 20151211